Canadian dinosaur closely related to mammals

A dinosaur fossil originally discovered on Prince Edward Island has been shown to have steak knife-like teeth, and Canadian researchers have changed its name to Dimetrodon borealis - marking the first occurrence of a Dimetrodon fossil in Canada.

"It's really exciting to discover that the detailed anatomy of the teeth has finally allowed us to identify precisely this important Canadian fossil," said lead author Kirstin Brink from the University of Toronto Mississauga.

"Dimetrodon is actually more closely related to mammals than it is to dinosaurs. In fact, it is believed they went extinct some 40 million years before the dinosaurs," Brink explained.

The fossil, previously known at Bathygnathus borealis, was collected in 1845, and was named Bathygnathus (meaning deep jaw) borealis (from the north) by palaeontologist Joseph Leidy.

Actually, Leidy mistook it as the lower jaw of a dinosaur, similar to the large bipedal species that were being collected in Europe at the time.

The Bathygnathus specimen was the first dinosaur, and the second vertebrate fossil named from Canada.

Now the researchers from University of Toronto, Carleton University and the Royal Ontario Museum found that the eight preserved teeth linked the fossil to the Dimetrodon family.

"These are blade-like teeth with tiny serrations along the front and back of the teeth, similar to a steak knife. This type of tooth is very effective for biting and ripping flesh from prey," explained senior author professor Robert Reisz.

The study appeared in the Canadian Journal of Earth Sciences.